BORDERS

Red over Blue

box-shadow:0px 0px 10px 1px red, 0px 0px 10px 5px blue;

 Blue over Red inset

box-shadow:0px 0px 10px 1px blue ;inset, 0px 0px 10px 5px red inset;

 Yellow over Red

box-shadow:0px 0px 10px 1px yellow, 0px 0px 10px 5px red;

 Red over Yellow inset

box-shadow:0px 0px 10px 1px red inset, 0px 0px 10px 5px yellow inset;

 Blue over Yellow

box-shadow:0px 0px 10px 1px blue, 0px 0px 10px 5px yellow;

 Yellow over Blue inset

box-shadow:0px 0px 10px 1px yellow inset, 0px 0px 10px 5px blue inset;